The present disclosure relates to a sewing machine.
In related art, a device is known that is configured to identify a position that is indicated by an ultrasound pen that transmits ultrasonic waves.
For example, a known ultrasound pen includes two transmitters. When a user indicates a position on a liquid crystal display panel using the ultrasound pen, a switch that is incorporated in a pen tip is turned on. When the switch is turned on, the two transmitters transmit ultrasonic waves. A receiver is provided in the vicinity of the liquid crystal display panel. The receiver receives the two ultrasonic waves transmitted by the two transmitters. Based on a difference between times at which the receiver receives the two ultrasonic waves, a pen input display device detects an inclination of the pen with respect to the liquid crystal display panel when the position on the liquid crystal display panel is indicated using the pen. The pen input display device identifies the position of the pen tip based on the inclination of the pen.
Further, for example, another known sewing machine can specify a sewing position using an ultrasound pen. When a user presses the pen tip of the ultrasound pen against a bed (when the user indicates a position), a switch of the ultrasound pen is turned on. When the switch is turned on, a transmitter of the ultrasound pen transmits an ultrasonic wave. The sewing machine is provided with a receiver. The receiver receives the ultrasonic wave transmitted by the transmitter. Based on a time at which the transmitter transmits the ultrasonic wave and a time at which the receiver receives the ultrasonic wave, the sewing machine identifies a position of the transmitter on the bed. The position of the transmitter and the position of the pen tip are close to each other. Therefore, the sewing machine assumes that the transmitter and the pen tip are located in the same position, and identifies the indicated position indicated by the pen tip.